The field of the invention is gas turbine control systems and, in particular, systems for monitoring and diagnosing gas turbine operation.
Accurately determining the operating modes of a gas turbine is useful in monitoring and diagnosing the operation of a gas turbine. Remote monitoring of gas turbines, especially industrial gas turbines, has become increasingly common. For example, technicians employed by a manufacturer of the gas turbine may remotely analyze information regarding the operation of the gas turbine at a customer site and prescribe corrective steps, such as party replacements or operation adjustments. The replacement of parts and operation adjustments may be performed by on-site operators of the gas turbine. To remotely analyze and diagnose data collected form a gas turbine, accurate information regarding the operating modes of the gas turbine is useful.
Large industrial gas turbines may transition through many operating modes from start up to shut down. In a general sense these operational modes may include Startup, Shutdown, Steady State, Thermal Instability, and Load Instability. Within each of these major modes may be one or more sub-modes of operation for the gas turbine. Associated with each of these major modes and sub-modes are operational parameters, e.g., vibration, temperatures, fuel and gas flows, heat rates and thermal efficiencies. Each of these parameters may have prescribed ranges for normal operation given a particular operating mode and sub-mode of the gas turbine. The normal ranges of these operational parameters may change from mode to mode, and sub-mode to sub-mode. An operational parameter of the gas turbine may be well within a normal range for a particular mode/sub-mode, but outside the normal ranges for some other mode/sub-mode.
In order to determine whether a particular operational parameter is within normal range it is helpful to know that particular mode/sub-mode in which the gas turbine is operating. Knowing the current operational mode/sub-mode of a gas turbine, a technician may be able to better determine whether the current values for vibration, temperatures, flow rates, heat rates, efficiencies and other conditions of the gas turbine are within normal operating ranges for those values. In addition, knowing the operational mode of a gas turbine is helpful when comparing the operation of the gas turbine to its historical operation under similar operating conditions and to other similar gas turbines.
There is a long-felt need for an algorithm for determining the operational mode and sub-modes of an industrial gas turbine. Further, there is a need for an algorithm that generates an easy to use value that designates the operational mode/sub-mode of the gas turbine.
In a first embodiment the invention is a method for determining an operating mode of a gas turbine comprising: monitoring at least one operating condition of the gas turbine; using the operating condition to categorize an operating mode of the gas turbine into one of the plurality of predetermined operating modes, and assigning a value to the categorized operating mode where the value is a number that is a power of a predetermined base number.